Sciencemadness Discussion Board - Propane as an inert-gas

Propane as an inert-gas

thechemMo - 30-9-2018 at 01:45

I know there has kinda been a thread about that.I wanna make it a little bit more specific,though.
I’ve read a thread on HIVE about the demethylation of Ethylvanilin to give protocatechuic aldehyde https://chemistry.mdma.ch/hiveboard/novel/000291912.html .The paper mentioned in this thread used Argon as an inert.I wanna use propane because it’s more excessebile and cheap.I don’t see anything against this „theory“ but I’m a little bit worried about explosion dangers.I‘d do it like this:3 neck rb flask,left neck I’d attach the tube that is connected to my propane tank with a suitable Glas Adapter.In the middle neck I‘d have my Friedrich condenser where I would on the top attach a „tube adapter“ made from Glas to let the propane gas get out of the apparatus(an then it would be ignited with a torch or something so that nothing comes into the atmosphere ).On the right neck Id just have my thermometer quick fit.Do u think that would work?

[Edited on 30-9-2018 by thechemMo]

Sulaiman - 30-9-2018 at 10:00

You could consider bubbling the exhaust gas through water to act as a flame trap ?

unionised - 30-9-2018 at 10:04

Did you consider CO2?

macckone - 30-9-2018 at 22:36

Argon is available as 'wine preserving' gas in fine wine stores.
If argon is unavailable, I would suggest butane rather than propane.
Butane can be bought without odorant.
To my knowledge propane cannot.
The thiol used as an odorant may cause issues.
If you use butane make sure you do it outside and use a flame arrestor on the outlet.
Unless you are working in a real lab and it is ethyl ether rated.
Butane has similar LEL and a higher activation energy than ethyl ether.

zed - 2-10-2018 at 12:21

It is possible CO2 will serve?

Might be sufficiently inert under your reaction conditions, and it is easy to generate.

I've seen Argon tanks at "Harbor Freight", in the past.

But, a current search of their site, shows none advertised.

ninhydric1 - 2-10-2018 at 19:49

Or use nitrogen gas. Remove the O2 from the atmospheric air with a flame and use water to absorb CO2. Send the gas through sulfuric acid to dry it. Or you could buy it if you have access to it.

morganbw - 5-10-2018 at 13:50

I would try the reaction without the inert gas. Maybe it is needed but sometimes it becomes a habit that is used with all trials.

I did not see any results shown without the inert gas.
For me (skip the inert) would be the first trial, then if that sucked I would think that, yay maybe it needs to be inert.

Tsjerk - 5-10-2018 at 13:56

With these phenols I would advise using a inert gas. They are prone to polymerizationand somehow it seems oxygen induced. Propane should work, just don't set it on fire

morganbw - 5-10-2018 at 14:53

Quote: Originally posted by Tsjerk

With these phenols I would advise using a inert gas. They are prone to polymerizationand somehow it seems oxygen induced. Propane should work, just don't set it on fire

You are more than likely right. I really understand this and respect this.

I am however a little reckless at times and am willing to trash a few grams of a substance just to satisfy my curiosity.

Dang, it looks as if I have just decided on a future experiment/synthesis for myself. No worries, I have failed a few times in the past. Still?

deep_dreamer - 6-10-2018 at 01:14

I have read a post (probably here on Sciencemadness) by a knowledgeable user that inert gas is not always necessary with catechols. Sadly, I can't find it anymore. It stated that the main problem is the oxygen already dissolved in the solvent, which could be fixed by boiling the solvent prior usage or by addition of a small amount of (I believe) a bisulfite salt (not too much, as to not interfere with the aldehydes).

Takes this with a grain of salt because:
1) I am not experienced enough to say if this works
2) I can not remember the original post
3) Even the original post was not backed up with any scientific data and merely anecdotal!

I believe it's better to be safe than sorry and use a decent inert gas.

PS: If someone finds the post I am referring to, please provide it.

Swinfi2 - 6-10-2018 at 20:07

I've worked with catechols, their stable enough dry in air and in degassed water, it is the wet oxygen that kills them.

[Edited on 7-10-2018 by Swinfi2]

wg48 - 6-10-2018 at 23:39

Catechol and other phenol derivatives were and probable still are used as silver halide developers. Meaning they were used in water solutions in baths open to the air for many hours. Typically the developers included sulphite to prevent air oxidation of the catechol.

I don’t know if the sulphite was able to reduce oxidised catechol or if it only acted as a oxygen scavenger being oxidised in preference to the catechol.

Another OTC argon

CaptainPike - 8-10-2018 at 19:38

There is also another retail source of argon, five nines

http://www.bloxygen.com/

You don't get very much – it's a low pressure container, but it's very pure. Maybe you could just fill the headspace occasionally during the reaction.

[Edited on 9-10-2018 by CaptainPike]

[Edited on 9-10-2018 by CaptainPike]

walruslover69 - 9-10-2018 at 06:09

I don't know what is available where you live, but every Walmart near me sells helium tanks. They aren't that expensive.

VSEPR_VOID - 18-10-2018 at 16:29

I am not sure if that helium is very pure.

Nitrogen is cheap and you can get it from welding supply stores locally.

Propane sounds like a bad idea. If there is any O2 remaining in the reaction vessel, you just made a bomb.

Twospoons - 18-10-2018 at 16:51

A lot of the OTC helium has oxygen in it to stop people suffocating while playing the voice changing game.

You should be able to get Ar or Ar/CO2 shield gas in single use cylinders at a welding supply shop.

[Edited on 19-10-2018 by Twospoons]

Morgan - 18-10-2018 at 17:14

That would be an experiment to try to test for oxygen in helium for balloons. I know one thing, it makes you dizzy when you do the squeaky voice thing. What percentage of O2 is cited in helium for balloons, from what reference if anyone knows or if any at all? Would it support combustion for example?

I should say I've only tried the store-bought balloons, not those lower volume, round tanks the public can buy for parties.

[Edited on 19-10-2018 by Morgan]

BromicAcid - 18-10-2018 at 17:27

Use nitrogen?

http://www.sciencemadness.org/talk/files.php?pid=505259&...

VSEPR_VOID - 18-10-2018 at 18:10

Quote: Originally posted by Morgan

That would be an experiment to try to test for oxygen in helium for balloons. I know one thing, it makes you dizzy when you do the squeaky voice thing. What percentage of O2 is cited in helium for balloons, from what reference if anyone knows or if any at all? Would it support combustion for example?

I should say I've only tried the store-bought balloons, not those lower volume, round tanks the public can buy for parties.

[Edited on 19-10-2018 by Morgan]

I bet it would not be hard to do an assay and find out. Find a reaction that requires bubbling oxygen through a solution to get a precipitate, put a liter of store bought He in, weight the precipitate, calculate O2 content

macckone - 19-10-2018 at 20:27

The walmart helium literally says on the tank that it contains oxygen.
If you are going to get a tank from a gas supplier, argon is way cheaper.
Propane is not any more dangerous than ethyl ether.
In fact ethyl ether is in some respects more dangerous.
Any reaction needing inert gas is likely going to be using either ether or another organic

Morgan - 20-10-2018 at 05:17

I see Balloon time helium is or says it's a "mixture of helium and air containing not less than 80% helium" that's for sale at PartyCity looking at the literature written on a tank from a photo from their site.

macckone - 20-10-2018 at 19:33

Morgan: that is the same stuff. In 2011 NZ corner Ian Smith recommended that helium from balloon time contain a minimum of 10% oxygen to prevent both accidental and intentional death. Shortly after the new mix started hitting shelves. Here is the worthington datasheet which provides the product for Balloon Time. I suspect Air is actually straight oxygen and they are shooting for 10-15% oxygen.

Attachment: wc042-helium-blend.pdf (30kB)
This file has been downloaded 298 times

[Edited on 21-10-2018 by macckone]

Morgan - 21-10-2018 at 06:19

Macckone I guess if it was just a He and air mix, then it would contain less than 5% O2. But yes, it does seem suspect in that the way foods and products are labeled these days, you never know if there may be obfuscations.
As an aside, there's something ironic about a person ending their life with a product called Balloon time. When I worked for a library, we had the book Final Exit in Large Print and that too was in a sense quirky.
https://exitinternational.net/?wysija-page=1&controller=...

unionised - 21-10-2018 at 06:55

Quote: Originally posted by Morgan

What percentage of O2 is cited in helium for balloons, from what reference if anyone knows or if any at all?
[Edited on 19-10-2018 by Morgan]

In principle, none.

They do not add oxygen to "balloon gas".
That idea is a dangerous myth.

The safety data sheet for Balloon gas is the same as the one for higher grades of helium.
https://www.boconline.co.uk/en/images/10021690_tcm410-84477....

If they added oxygen they would be expected to ensure that the rest of it was "breathing grade" and that would make it much more expensive.

Balloon gas is cheap "dirty" helium.
When a research lab or whoever returns an "empty" cylinder to the supplier, they first thing they have to do is empty it y hooking it to a vacuum pump.

Similarly, when they fill high purity helium cylinders, they have to purge air out of the manifolds with helium.

Both those processes give rise to He containing a bit of air.
That's "balloon gas".

The specification that was cited earlier includes 0% air as a possibility.

[Edited on 21-10-18 by unionised]

Morgan - 21-10-2018 at 07:11

I was wondering if you put Balloon time helium in a burette with an electrically heated platinum wire or gauze you could slowly introduce hydrogen to keep it below any possible lower explosive limit and burn up the oxygen to confirm what volume of helium and nitrogen remains.
I can't think of any simple getters for oxygen the way limewater works for CO2.

[Edited on 21-10-2018 by Morgan]

unionised - 21-10-2018 at 07:21

Quote: Originally posted by Morgan

I can't think of any simple getters for oxygen the way limewater works for CO2.

[Edited on 21-10-2018 by Morgan]

The traditional ones are alkaline solutions of pyrogallol or chromous chloride, or powdered iron or copper in the presence of ammonia and ammonium chloride solution.

From a home chemist perspective...
https://en.wikipedia.org/wiki/Hand_warmer#Air_activated_(iron)

Morgan - 21-10-2018 at 17:27

There was this cobalt compound said to be able to absorb all the O2 out of a room from phys.org. I suppose the spoonful is actually put over a large surface area like the way platinum is used on carbon or alumina?
"The material is so effective at binding oxygen, that only a spoon of it is enough to suck up all the oxygen in a room."
Read more at: https://phys.org/news/2014-09-material-oxygen-air.html#jCp

Another slant ..
https://motherboard.vice.com/en_us/article/8qxvna/this-new-o...

[Edited on 22-10-2018 by Morgan]

wg48 - 21-10-2018 at 19:54

Quote: Originally posted by Morgan

There was this cobalt compound said to be able to absorb all the O2 out of a room from phys.org

That’s BS you can not squeeze the oxygen from a room of air in to the volume of a spoon full of anything as its density would be greater than any known material excluding neutron star material and black holes and assumes regular table spoons and typical room sizes.

Morgan - 22-10-2018 at 11:38

Quote: Originally posted by wg48

Quote: Originally posted by Morgan

There was this cobalt compound said to be able to absorb all the O2 out of a room from phys.org

Your reaction was about the same as mine but I wondered how phys.org could be posting the nonsense. There were about a dozen articles that had the same basic wording including Popular Science. They all ran with the same spoonful story. But then I thought maybe there was some possible way to transfer O2 to a bulk quasi -zeolite type substrate with a coating of the active ingredient, thinking perhaps that's what they meant. Anyway phys.org has shown itself on this occasion to be a fizz.org.

From the bottom of the page from the second link I posted ...quite a calculation error all around.
"Update 10/1: We've updated this post to correct a calculation error on the part of the researchers that suggested the oxygen-absorbing compound is far more efficient than it actually is. In an emailed statement, a representative for Syddansk University said "I am just updating our story on our website, because it turns out that Prf McKenzie made a calculation error. Pls note that it is not a SPOONFUL of this stuff, that we need to rid a room of oxygen. It is a bucket (10 litres). We apologize." Motherboard apologizes for any confusion."
https://motherboard.vice.com/en_us/article/8qxvna/this-new-o...

[Edited on 22-10-2018 by Morgan]

unionised - 22-10-2018 at 12:07

Would anyone like to do the arithmetic on a bucket of coal or magnesium turnings?

I suspect that stuff is nothing special in terms of O2 trapping.

wg48 - 22-10-2018 at 13:27

Quote: Originally posted by Morgan

Quote: Originally posted by wg48

Quote: Originally posted by Morgan

There was this cobalt compound said to be able to absorb all the O2 out of a room from phys.org

I was surprised no one had commented how ridiculous the statement was. My first mental guesstimate was a cubic foot of material would be required (yes I still think in imperial units when i want a feel for the size of something). I assumed it was hype to increase the chance of more funding or snagging gullible investors.

As a cross check: there is about .0.25kg of oxygen in a 1m^3 of air, if you assume 10l has the unrealistically high storage density of liquid oxygen (approximately the density of water ) that’s 10kg of oxygen or 40 m^3 or a 3.4m cube of air.. A more realistic storage capacity is say 10% of that of liquid oxygen making it a cube of 1.6m of air, ok a small room but close enough to be not immediately ridiculous.

macckone - 22-10-2018 at 20:47

Let's run the numbers.
1 mole of activated iron will absorb 1.5 moles of oxygen.
So 56 grams will absorb 33.6L but oxygen is approximately 1/5 of air.
So that would be about 170L of air, of course we are only removing the oxygen portion.
A tablespoon would be 2 moles of iron or 340L of air.

BUT you only need to remove 10% of the oxygen in air to be dangerous.
so a tablespoon of activated iron would reduce oxygen enough to be dangerous in a 3.4m^3 room if spread carefully and totally sealed.
So not much more than a closet.

A 3 x 3M room with a 2.4M high ceiling (approx 10 x 10 x 8ft) would require 63 tablespoons.
about 3.6 kg of activated iron or about a half liter (density 7.87 - the granulating would make it lighter).

boron hydride is going to do better.
of course neither activated iron nor boron hydride is going to be reversable.

wiglaf - 24-10-2018 at 05:35

Thanks for the calculation. It's educational. FWIW, the iron would be far less dense than assumed (no way to get 2 moles of powdered iron in a Tablespoon)

Except for the danger of having your closet implode from sudden depressurization, removing 10% of the oxygen is likely not "dangerous". Since you're over a mile high, you already have 15-20% less oxygen than I do (lucky!).

Tsjerk - 24-10-2018 at 06:02

"Serious side effects can occur if the oxygen levels drop outside the safe zone. When oxygen concentrations drop from 19.5 to 16 percent, and you engage in physical activity, your cells fail to receive the oxygen needed to function correctly. Mental functions become impaired and respiration intermittent at oxygen concentrations that drop from 10 to 14 percent; at these levels with any amount of physical activity, the body becomes exhausted. Humans won't survive with levels at 6 percent or lower."

source: https://sciencing.com/minimum-oxygen-concentration-human-bre...

Morgan - 24-10-2018 at 06:20

I remember some mention of oxygen when taking flying lessons, where flying at some particular elevation at night the instructor said taking a few breaths of pure oxygen was like turning the rheostat up on the instrument panel, the brightness increased.

macckone - 24-10-2018 at 19:51

Where I am removing 10% of the oxygen would definitely be dangerous. Altitude sickness kills people all the time in the denver area, mostly via heart attack. The worst locally is people flying in and then immediately driving up mt evans (14K feet) which has a pressure of 8.2psi (56% of normal - equivalent to 12% oxygen). Altitude sickness actually takes a bit of time to kill you though. Where I am, it isn't that bad though. A mile high is about 20% less, I have less oxygen than that.

And notice I said dangerous, not deadly.

The first effect of low oxygen is increased pulse. Next your body starts trying to remove liquid from your blood, reducing your blood volume. Then your body releases blood cells from your spleen. Finally it starts producing more red blood cells. In some people the red blood cells are larger. In others they actually significantly increase the red blood cell counts.

This can lead to heart attack or stroke if you have even slightly clogged arteries.
Altitude sickness itself can lead to pulmonary or cerebral edema.

VSEPR_VOID - 25-10-2018 at 05:34

Quote: Originally posted by macckone

Let's run the numbers.
1 mole of activated iron will absorb 1.5 moles of oxygen.
So 56 grams will absorb 33.6L but oxygen is approximately 1/5 of air.
So that would be about 170L of air, of course we are only removing the oxygen portion.
A tablespoon would be 2 moles of iron or 340L of air.

BUT you only need to remove 10% of the oxygen in air to be dangerous.
so a tablespoon of activated iron would reduce oxygen enough to be dangerous in a 3.4m^3 room if spread carefully and totally sealed.
So not much more than a closet.

A 3 x 3M room with a 2.4M high ceiling (approx 10 x 10 x 8ft) would require 63 tablespoons.
about 3.6 kg of activated iron or about a half liter (density 7.87 - the granulating would make it lighter).

boron hydride is going to do better.
of course neither activated iron nor boron hydride is going to be reversable.

There was an incident where one Marine armed with a flamethrower killed something like 50 Japanese infantry with one short burst. the reason why was because he fired into the entrance of a cave, which cause a large amount of CO to drift down into the tunnel system. The result was CO poisoning of all the infantry inside.

So a few liters of CO is better than a few Kg of activated iron for clearing rooms.

wiglaf - 25-10-2018 at 08:18

I was referring to a 10% drop in oxygen levels (relative to starting) - NOT 10% oxygen! In other words going from 21% Oxygen to 19%. No doubt that 10% (absolute level vs 21% at standard) is dangerous. I was only trying to point out that a sudden absorption of 10% of the oxygen in the room would be likely to lower the pressure enough to cause to the walls to buckle.

wg48 - 25-10-2018 at 09:44

Quote: Originally posted by macckone

Where I am removing 10% of the oxygen would definitely be dangerous. Altitude sickness kills people all the time in the denver area, mostly via heart attack. The worst locally is people flying in and then immediately driving up mt evans (14K feet) which has a pressure of 8.2psi (56% of normal - equivalent to 12% oxygen). Altitude sickness actually takes a bit of time to kill you though. Where I am, it isn't that bad though. A mile high is about 20% less, I have less oxygen than that.

And notice I said dangerous, not deadly.

If they arrived by jet airliner they have already been subject to about 33% less partial pressure of oxygen due to the reduced cabin pressure. Its what can make your legs swell and ache on long flight not just lack of activity for so many hours.

Morgan - 25-10-2018 at 14:58

From Cabin Pressurization topic in Wiki ...
"Scuba divers flying within the "no fly" period after a dive are at risk of decompression sickness because the accumulated nitrogen in their bodies can form bubbles when exposed to reduced cabin pressure."

"The FAA’s Airman’s Information Manual (AIM) offers a small section entitled “Decompression Sickness After Scuba Diving” that indicates “a pilot or passenger who intends to fly after scuba diving should allow the body sufficient time to rid itself of excess nitrogen absorbed during diving. If not, decompression sickness due to evolved gas can occur during exposure to low altitude and create a serious in-flight emergency.”
https://www.tdisdi.com/scuba-diving-and-flying/

macckone - 25-10-2018 at 21:04

wg48:
Altitude sickness is actually made worse by the flight.
It isn't an instant reaction, it takes about 24 hours to develop.
But some people can have reactions that take longer.
The nederland police chief resigned in 2014 because he couldn't adjust to the altitude (8228 ft).

nederland is a crappy little mountain town as they are fond of saying in south park.
south park aka fairplay is actually at a higher altitude (10K ft).
Alma is also in park county and is the highest inhabited town in the united states at 10,578ft.
http://www.townofalma.com/

Morgan:
yes very dangerous. don't dive and fly.